Hitherto, as a process for producing a porous TFE polymer tube, there is known a production process thereof by expanding an unsintered tubular product of a paste extrusion-molded TFE polymer to the radial direction of the tube and thereafter heat-treating the tube at a temperature of at least the melting point of the TFE polymer (Japanese Patent publication No. 17216/81 which corresponds to U.S. Pat. No. 3,953,566).
Also, as a process for producing a non-porous TFE polymer tube having heat-shrinkability, there is known a production process thereof by imparting stress to a TFE polymer tube at a temperature within the range of from the softening point thereof to the pour point thereof to expand the tube and immediately fixing it by cooling (Japanese Patent Publication No. 29635/71).
However, the porous TFE polymer tube obtained by the former production process is poor in heat shrinkability, while the TFE polymer tube obtained by the latter production process has heat shrinkability but is not porous. Thus, a TFE polymer tube which is porous and has heat shrinkability and a production process of such a TFE tube have not yet been known.